High power InGaAsSb(Gd)/InAsSbP double heterostructure lasers (λ=3.3 µm)

InGaAsSb(Gd)/InAsSbP double heterostructure lasers (λ=3.3 μm, T=77 K) yield a multimode power of 1.56 W in pulsed operation (pulse width 30 μs, repetition frequency f=500 Hz) and 160 mW in the continuous-wave (CW) case. In the single-mode CW operation, the power is 18.7 mW. It is shown that heating of the active region is responsible for sublinear light-current characteristics in “long-cavity” lasers, whereas in “short-cavity” (L=140–300 μm) lasers the power is mainly limited by internal losses. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 35, No. 10, 2001, pp. 1261–1265. Original Russian Text Copyright ? 2001 by Aydaraliev, Zotova, Karandashev, Matveev, Remennyi, Stus’, Talalakin.     

Infrared light-emitting diodes based on GaInAsSb solid solutions grown from lead-containing solution-melts

Light-emitting diodes (LEDs) were fabricated on the basis of GaInAsSb alloys grown from lead-containing solution-melts. Electroluminescence characteristics and their current and temperature dependences were studied. The external photon yield at room temperature was 1.6 and 0.11% for LEDs with emission wavelengths λ=2.3 and 2.44 μm, respectively. For LEDs with emission wavelength λ=2.3 μm, the average emission power P=0.94 mW was attained in the quasi-continuous mode at room temperature. In the pulsed mode, the peak radiation power was P=126 mW at a current of 3 A, a pulse duration of 0.125 μs, and a frequency of 512 Hz. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 38, No. 12, 2004, pp. 1466–1472. Original Russian Text Copyright ? 2004 by Astakhova, Grebenshchikova, Ivanov, Imenkov, Kunitsyna, Parkhomenko, Yakovlev.     

Difference mode generation in injection lasers

The nonlinear generation of a difference mode in an injection laser is considered. A new design based on the InGaP/GaAs/InGaAs heterostructure is suggested in order to generate two laser modes with a wavelength of about 1 μm and a difference mode at a wavelength of about 10 μm. In lasers with a 100-μm-wide waveguide, the power output of the difference mode can be as high as ∼10 mW at ∼10 W in the short-wavelength modes. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 35, No. 10, 2001, pp. 1256–1260. Original Russian Text Copyright ? 2001 by Aleshkin, Afonenko, Zvonkov.     

Room temperature continuous wave operation of quantum cascade laser at λ～ 9.4μm

Continuous wave (CW) operation of long wave infrared (LWIR) quantum cascade lasers (QCLs) is achieved up to a temperature of 303 K.For room temperature CW operation,the wafer with 35 stages was processed into buried heterostructure lasers.For a 2-mm-long and 10-μm-wide laser with high-reflectivity (HR) coating on the rear facet,CW output power of 45 mW at 283 K and 9 mW at 303 K is obtained.The lasing wavelength is around 9.4μm locating in the LWIR spectrum range.     

High-power light-emitting diodes operating in the 1.9 to 2.1-µm spectral range

Light-emitting diodes (LED’s) operating in the spectral range 1.9–2.1 μm have been fabricated by liquid-phase epitaxy on the basis of AlGaAsSb/GaInAsSb double heterostructures with a high Al (64%) content in the wide-gap regions. The design of the LED makes it possible to locate the active region near the heat-removal elements of the housing, and pass the light through the GaSb substrate, which is completely unshielded by the contact. The LED’s are investigated in the quasi-continuous (CW) regime and pulsed regime at room temperature. The optical power of the LED’s possesses a linear current dependence over a wide range of currents. A CW optical power as high as 4.6 mW and a peak optical power of 190 mW in the pulsed regime were achieved at room temperature. It is shown that the transition from linear to sublinear current dependence of the optical power is governed by Auger recombination in the pulsed regime at pulse durations as low as 5 μs. Fiz. Tekh. Poluprovodn. 33, 239–242 (February 1999)     

GaAs-based 1.3 µm InGaAs quantum dot lasers: A status report

We review the present status of InGaAs quantum dot lasers on GaAs sub-strates emitting near and at 1.3 μm. Such lasers are shown to be extremely promising for cost-efficient commercial applications in optical fiber communication. Threshold current densities a low as ∼20 Acm⁻² per QD sheet are achieved. Room temperature continuous wave operation at 2.7 W for broad stripe devices is demonstrated. The maximum differential efficiency amounts to 57%. Moreover, single lateral mode continuous wave operation with a maximum output power of 110 mW is realized. Prospects for 1.3 μm GaAs-based vertical cavity surface emitting lasers are given. We also show that the longest wavelength of QD GaAs-based light emitting devices can be potentially extended to 1.7 μm.     

InAsSb/InAsSbP diode lasers with separate electrical and optical confinement, emitting at 3–4 µm

Diode lasers based on InAsSb/InAsSbP with separate electrical and optical confinement, emitting in the wavelength interval 3–4 μm, are investigated. The lasers attain a higher operating temperature when electrical confinement is created by means of type-II heterojunctions. Interface Auger recombination is suppressed in lasers of this type, and the experimental current density is close to the theoretically calculated value for the case of predominant volume Auger recombination at a temperature of 180–220 K. Fiz. Tekh. Poluprovodn. 31, 976–979 (August 1997)     

Energy spectrum of acceptors in the semimagnetic semiconductors p-Hg1−x MnxTe in the spin-glass region

The far-IR transmission and photoconductivity in the semimagnetic alloys p-Hg_1−x Mn_xTe (x=0.20–0.22) at temperatures 2–7 K were investigated at fixed frequencies of optically pumped molecular lasers in the region 49–311 μm. We report the observation of photoexcitation of acceptors from the ground into excited states under conditions when the direct interaction of the magnetic moments of the manganese ions becomes substantial and results in the formation of a spin-glass phase. It was found that the internal field produced by the spontaneous and external polarizations of the magnetic moments of the Mn²⁺ ions in the spin-glass temperature range influences the energy spectrum of acceptors in a magnetic field. Fiz. Tekh. Poluprovodn. 32, 450–452 (April 1998)     

A spatially single-mode laser for a range of 1.25–1.28 μm on the basis of InAs quantum dots on a GaAs substrate

Spatially single-mode lasing in the wavelength range of 1.25–1.28 μm was accomplished in injection lasers on GaAs substrates. The peak output power is 110 mW at room temperature, and the differential quantum efficiency amounts to 37%. The active region of the laser is formed by an array of self-organizing InAs quantum dots. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 1, 2000, pp. 117–120. Original Russian Text Copyright ? 2000 by Mikhrin, Zhukov, Kovsh, Maleev, Ustinov, Shernyakov, Kayander, Kondrat’eva, Livshits, Tarasov, Maksimov, Tsatsul’nikov, Ledentsov, Kop’ev, Bimberg, Alferov.     

Distributed feedback quantum cascade lasers operating in continuous-wave mode at λ≈7.6μm

正Distributed feedback(DFB) quantum cascade lasers(QCLs) in continuous-wave(CW) mode emitting atλ≈7.6μm are presented.Holographic lithography was used to fabricate the first-order distributed feedback grating. For a high-reflectivity-coated QCL with 14.5-μm-wide and 3-mm-long cavity,CW output powers of 300 mW at 85 K and still 10 mW at 270 K are obtained.Single-mode emission with a side-mode suppression ratio(SMSR) of about 30 dB and a wide tuning range of ~300 nm in the temperature range from 85 to 280 K is observed.     

High-power 1.5 µm InAs-InGaAs quantum dot lasers on GaAs substrates

Light-current, spectral, and temperature characteristics of long-wavelength (1.46–1.5 μm) lasers grown on GaAs substrates, with an active area based on InAs-InGaAs quantum dots, are studied. To reach the required lasing wavelength, quantum dots were grown on top of a metamorphic InGaAs buffer layer with an In content of about 20%. The maximum output power in pulsed mode was 7 W at room temperature. The differential efficiency of the laser, which had a 1.5-mm-long cavity, was 50%. The temperature dependence of the threshold current is described by a characteristic temperature of 61 K in the temperature range 10–73°C. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 38, No. 6, 2004, pp. 763–766. Original Russian Text Copyright ? 2004 by Maksimov, Shernyakov, Kryzhanovskaya, Gladyshev, Musikhin, Ledentsov, Zhukov, Vasil’ev, Kovsh, Mikhrin, Semenova, Maleev, Nikitina, Ustinov, Alferov.     

Ultralow internal optical loss in separate-confinement quantum-well laser heterostructures

Internal optical loss in separate-confinement laser heterostructures with an ultrawide (>1 smm) waveguide has been studied theoretically and experimentally. It is found that an asymmetric position of the active region in an ultrawide waveguide reduces the optical confinement factor for higher-order modes and raises the threshold electron density for these modes by 10–20%. It is shown that broadening the waveguide to above 1 μm results in a reduction of the internal optical loss only in asymmetric separate-confinement laser heterostructures. The calculated internal optical loss reaches ∼0.2 cm⁻¹ (for λ≈1.08 μm) in an asymmetric waveguide 4 μm thick. The minimum internal optical loss has a fundamental limitation, which is determined by the loss from scattering on free carriers at the transparency carrier density in the active region. An internal optical loss of 0.34 cm⁻¹ was attained in asymmetric separate-confinement laser heterostructures with an ultrawide (1.7 μm) waveguide, produced by MOCVD. Lasing in the fundamental transverse mode has been obtained owing to the significant difference in the threshold densities for the fundamental mode and higher-order modes. The record-breaking CW output optical power of 16 W and wallplug efficiency of 72% is obtained in 100-μm aperture lasers with a Fabry-Perot cavity length of ∼3 mm on the basis of the heterostructures produced. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 38, No. 12, 2004, pp. 1477–1486. Original Russian Text Copyright ? 2004 by Slipchenko, Vinokurov, Pikhtin, Sokolova, Stankevich, Tarasov, Alferov.     

InAsSb/InAsSbP double-heterostructure lasers emitting in the 3–4 µm spectral range

Our earlier reports concerning the fabrication by liquid-phase epitaxy and investigation of InAsSbP/InAsSb/InAsSbP double heterostructure lasers emitting at 3–4 μm are reviewed. The dependences of spectral characteristics and the spatial distribution of the laser emission on temperature and current are discussed. Lasing modes are shifted by 0.5–1.0 cm⁻¹ to longer wavelengths with increasing temperature. The tuning of the lasing modes by means of current is very fast (10⁻⁸–10⁻¹² s). With increasing current, the modes are shifted to shorter wavelengths by 50–60 ? at 77 K. The maximum mode shift of 104 ? (10 cm⁻¹) is observed at 62 K. The spectral line width of the laser is as narrow as 10 MHz. Abnormally narrow directional patterns in the p-n junction plane are observed in some cases in the spatial distribution of laser emission. The current tuning of lasers, due to nonlinear optical effects, has been modeled mathematically in good agreement with the experiment. Transmittance spectra of OCS, NH₃, H₂O, CH₃Cl, and N₂O gases were recorded using current-tuned lasers. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 35, No. 12, 2001, pp. 1466–1480. Original Russian Text Copyright ? 2001 by Danilova, Imenkov, Kolchanova, Yakovlev. See [1].     

Optimization of GaAsP/AlGaAs-based QW laser structures for high power 800 nm operation

We present a detailed study of the MOVPE growth of 800 nm diode laser structures based on the combination of a GaAsP quantum well with well-established AlGaAs waveguide structures. By optimizing the strain and thickness of the quantum well highly-reliable diode lasers with low threshold current and high efficiency were demonstrated. 100 μm aperture “broad area” devices mounted epi-side up achieve a CW output power of 8.9 W with a wall-plug efficiency of 50%. These output powers represent record values for diode lasers in this wavelength range. Reliability measurements at 1.5 W and 50°C ambient temperature suggest lifetimes >10 000 h.     

Holographic fabricated continuous wave operation of distributed feedback quantum cascade lasers atλ≈8.5μm

The fabrication and characterization of distributed feedback（DFB） quantum cascade lasers emitting atλ≈8.5μm are reported.The first-order DFB grating structure was defined using the holographic lithography technique.Reliable dynamic single-mode emission with a side-mode suppression ratio of 20 dB and a tuning coefficient of-0.277 cm^-1/K from 93 to 210 K is obtained in continuous wave mode by using high-reflectivity coating on the rear facet.The output power is over 100 mW at a temperature of 80 K.     

High-temperature(T = 80℃) operation of a 2μm InGaSb-AlGaAsSb quantum well laser

正An InGaSb/AIGaAsSb compressively strained quantum well laser emitting at 2μm has been fabricated. An output power of 82.2 mW was obtained in continuous wave(CW) mode at room temperature.The laser can operate at high temperature(T = 80℃),with a maximum output power of 63.7 mW in CW mode.     

High-efficiency LEDs of 1.6–2.4 µm spectral range for medical diagnostics and environment monitoring

High efficient LED structures covering the spectral range of 1.6–2.4 μm have been developed on the basis of GaSb and its solid solutions. The electroluminescent characteristics and their temperature and current dependences have been studied. The radiative and nonradiative recombination mechanisms and their effect on the quantum efficiency have been investigated. A quantum efficiency of 40–60% has been obtained in the quasi-steady mode at room temperature. A short-pulse optical power of 170 mW was reached. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 37, No. 8, 2003, pp. 996–1009. Original Russian Text Copyright ? 2003 by Stoyanov, Zhurtanov, Astakhova, Imenkov, Yakovlev.     

A 5 mm×5 mm mid-wavelength infrared HgCdTe photodiode array with negative luminescence efficiency ∼95%

The negative luminescence (NL) efficiency of a 5 mm×5 mm array (100% effective fill factor) of HgCdTe photodiodes (λ_co=4.8 μm at 295 K) has been measured as a function of temperature. The internal NL efficiency of ≈95% at λ=4 μm is nearly independent of temperature in the 240–300 K range and, at 300 K, corresponds to an apparent temperature reduction of 60 K. This performance is obtained at a reverse-bias saturation-current density of only 0.11 A/cm² at 296 K. With large area, high efficiency, and low saturation-current density, our results demonstrate a level of NL device performance at which such applications as cold shields for large-format focal plane arrays (FPAs) and multipoint nonuniformity correctors appear practical.     

Nature of the edge electroluminescence peak in the Si:(Er,O) diode breakdown mode

Electroluminescence (EL) of erbium-and oxygen-doped Si:(Er,O) diodes at λ=1.00–1.65 μm has been studied in the p-n junction breakdown and forward current modes. The EL was measured at room temperature from the front and back surfaces of the diodes. A peak corresponding to the absorption band edge of silicon was observed in the EL spectra of some diodes in the p-n junction breakdown mode. The peak is associated with the injection of minority carriers from the metal contact into silicon, with subsequent band-to-band radiative recombination. The band-to-band recombination intensity increases sharply on reaching a certain current density that depends on the fabrication technology. This threshold current density decreases with the temperature of post-implantation annealing of Si:(Er,O) diodes increasing in the range 900–1100°C. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 36, No. 4, 2002, pp. 453–456. Original Russian Text Copyright ? 2002 by Emel’yanov, Nikolaev, Sobolev.     

Mobility of charge carriers in double-layer PbTe/PbS structures

The method of hot-wall epitaxy is used to grow epitaxial heterostructures of p-PbTe/n-PbS on BaF₂ substrates. Hall-effect measurements are analyzed in order to obtain the dependence of the effective carrier mobility on thickness and temperature in the ranges 0.1–2 μm and 100–300 K, respectively. It is found that this mobility depends on the thickness of the sample and on the individual thicknesses of its constituent layers. The effective mobility is calculated under the assumption that charge carriers are scattered by the surface of the structure and by dislocations that form at the heterojunction boundary. Fiz. Tekh. Poluprovodn. 32, 1064–1068 (September 1998)